Regulating the electronic structure of N-doped carbon enabled by B doping toward enhanced •OH generation for heterogeneous electro-Fenton oxidation

Synthesized the metal-free B and N co-doped porous carbon (B X NPC) catalysts. • Promoting •OH generation via B doping on B 50 NPC revealed by theoretical calculations. • •OH and 1 O 2 oxidation synergistically enhanced refractory antibiotics removal. • Treating actual pharmaceutical factory wastewater with a low energy consumption. • Excellent detoxification and disinfection performance of B 50 NPC electro-Fenton. Heterogeneous electro-Fenton (EF) is an attractive process for refractory and hazardous pollutants degradation that usually relies on •OH produced via the in-situ decomposition of electro-generated H 2 O 2 on metal-based catalytic sites, which faces the problems of metal shedding and leaching under acidic or even neutral conditions. Designing and investigating a bifunctional metal-free catalyst is a sensible strategy for the development of heterogeneous EF process. Herein, the bifunctional metal-free boron and nitrogen co-doped porous carbon (B X NPC) catalysts were prepared. Total organic carbon removals of hazardous and refractory antibiotics (ciprofloxacin, levofloxacin, sulfamethoxazole, tetracycline, and norfloxacin) by B 50 NPC EF process were 67 ± 2% − 90 ± 2% in 3 h. This process could efficiently treat actual pharmaceutical factory wastewater that chemical oxygen demand (COD) removal was 86.8 ± 1.3% with specific energy consumption of 3.7 ± 0.2–6.7 ± 0.1 kWh (kg COD) −1 superior to previous reports (5.5–290 kWh (kg COD) −1 ). Theoretical calculations and experiments revealed that the B sites and carbon defects in B 50 NPC promoted •OH and 1 O 2 generation, respectively, synergistically enhancing antibiotics removal. The results of toxicity evaluation and E. coli deactivation demonstrated excellent detoxification and disinfection performance. The results gain deep insights into the O 2 reduction mechanism of bifunctional metal-free B X NPC and developing an energy-efficient electrochemical process for promoting the decomposition of hazardous and refractory antibiotics. Download: Download high-res image (218KB) Download: Download full-size image